Aerial Detection Survey

How Surveys are Flown:

Each year during the summer and early fall Forest Health Protection and its partners conduct aerial surveys to map forest insect and disease activity in Region 2. Aerial surveys provide an annual snapshot of forest health conditions over large areas more efficiently and economically than other methods. To conduct the survey, observers in small aircraft record areas of activity using a digital aerial sketchmapping system that incorporates a tablet PC, geographic information systems and global positioning system technology. Aircraft used for these flights in the Rocky Mountain Region are typically small high-wing planes such as the Cessna T206 or T210. Aircraft fly in either a grid pattern over relatively flat terrain or following the contours of the terrain in mountainous or deeply dissected landscapes. The US Forest Service partners with State Cooperating Agencies in conducting the annual survey.

Grid pattern flown with two observers

Contour pattern flown with one observer

To identify insect and disease activity, the observer looks for characteristic signatures to distinguish the tree species and the type of damage that has occurred. Characteristics that observers use to determine the host tree species include: the shape of the tree’s crown, slope position, elevation and aspect. Variation in the color of the tree’s foliage indicates the presence and type of insect or disease activity. For example, bark beetle activity causes tree mortality which results in foliage color fading from green to a species specific yellow, red or straw color. In contrast, defoliators remove some of the foliage, resulting in discoloration such as a gray, red, or yellow tinge. During the survey all of the observed damages are recorded in a digital format which is compiled for use in the production of maps and summary statistics. When unknown signatures are observed, ground checks are conducted to verify the host and damage causing agent.

Pockets of ponderosa pine killed by mountain pine beetle above and to the left of Mt. Rushmore